1. Field of the Invention
The present invention relates to a vehicular automatic power transmission operating device in which an operating lever shifts into a range position of an automatic power transmission.
2. Description of the Related Art
A vehicular automatic power transmission operating device of the related art has a power assist unit that, for the purpose of easily shifting into a range position of an automatic power transmission, adds power assist force to operational force (rotational torque) resulting from an operation input unit.
The power assist unit is coupled to the operation input unit in two structures, that is, one structure in which the former is directly connected to the latter and the other structure in which the former is indirectly connected to the latter.
The structure in which the former is directly connected to the latter is disclosed in Japanese Patent Provisional Publication No. 11-286225. An operation input unit is accommodated inside of a case. A torque sensor is inserted to a sensor accommodating section formed in a lower end of an operating lever (forming one part of the operation input unit) at one end of the sensor accommodating section. An input shaft of the torque sensor is coupled to the operating lever through a splinted portion formed on the other end of the sensor accommodating section. An output shaft of the torque sensor is rotatably supported by the case through a bush. A rotary shaft of the operating lever corresponds to the input shaft and the output shaft of the torque sensor.
The structure in which the former is directly connected to the latter is described below. An operation input unit is fixed to a cross car beam, disposed inside of an instrument panel compartment, through a bracket. The torque sensor is connected to a lower lever (forming one part of the operation input unit) which is fixed to a lower end of the operating lever, via a control cable. If the operating lever bears load resulting from secondary collision, the operating lever is retracted into the instrument panel compartment while the lower lever moves toward a vehicle front to assume a position near a side of the cross car beam. To this end, the instrument panel compartment is provided with a space in an area close proximity to the side area of the cross car beam so as to move the lower lever toward the vehicle front.
The structure in which the former is directly connected to the latter suffers from an issue described below. The sensor accommodating section has one end formed with an opening with a large diameter for inserting the torque sensor therein. Since the large diameter has a larger tolerance range than a small diameter in the same tolerance class, assembling precision is deteriorated between the torque sensor and the sensor accommodating section, and then it becomes hard for the operating lever to adequately and smoothly rotate. Also, if assembling precision is deteriorated between the input shaft of the torque sensor and the splinted portion, it becomes hard for operational force of the operating lever to be correctly transferred to the torque sensor. Accordingly, the torque sensor is unable to correctly detect real operational force of the operating lever, and power assist force cannot be appropriately added to operational force. Additionally, if looseness occurs between the input shaft of the torque sensor and the splinted portion, the torque sensor is shaky to output unstable detected value.
Further, an upper end portion of the case cover is formed with an opening in older to insert the operating lever into the case. Provided between the operating lever and a peripheral-edge portion of the opening is a minute gap to allow the operating lever to rotatably slide. If a long distance exists between the opening and an operating knob which is mounted in an upper end of the operating lever, the operating lever is shaky to cause the unstable detected value to the torque sensor.
The structure in which the former is indirectly connected to the latter encounters an issue described below. Since the instrument panel compartment is provided with the space in the area close proximity to the side area of the cross car beam in order to move the lower lever toward the vehicle front, rearranged rearward of the vehicle are vehicle components to be originally displaced in the space. Therefore, the instrument panel and the operation input unit are displaced rearward of the vehicle in response to an area occupied by the vehicle components. Thus, a vehicle compartment tends to have a narrowed space.